TCEC is listed in the Lonely Planet guide book and can be a worthy place for you to visit as it will be fun and educational for you and your family.If you like to visit this place make sure that when you arrive at the centre, there are two large statues of turtles and a sign in Indonesian and English stating that it is the TCEC outside of the centre. This is because if you go by taxi,the driver might be misleading you to another turtle conservation which not recommended by Lonely Planet and usually those conservation centre might be fake or in a bad condition.
In the beginning of your tour you will be taken to the hatchery area were the eggs are buried beneath the sand labelled with the beach area from where they were collected, the date of collection, the number of eggs and the expected hatching date. Then you were shown a pool containing juveniles which had been injured or were ill and in rehab - they were to be released To this end you were shown a classroom area with some information with regards to the island of Serangan (Turtle Island) and how it had been destroyed by development (leading to problems for the islands Turtle populations as the beach no longer exists!).
The centre was also home to a few injured turtles that had been brought to the centre by concerned snorkellers and divers.There is a donation box but it does not in any way made to feel like you must contribute and also a small shop with some nice turtle shaped ornaments made from wood etc that, again you are under no obligation to purchase. But if you think your tour is informative,I encourage you to buy at those shop and made some donation as the money will be put to good use and to ensure the survival of the Bali sea turtle.